the white wire should not be used for lights, although some on this forum claim to have designed lights that work with the white wire. its just not a good idea. I use the white wire for connecting my killswitch. Again, members on the forum claim that the white wire can fail, short circuit, or otherwise fry the ignition coil. Been riding MB's for 3 years, never had a problem with the white wire myself. Some members wire the killswitch to the cdi, but im too lazy to figure that out. Easier to just hook one wire from the switch to the white wire and the other from the switch to ground. works the same, no matter what all the negative nellies say.